Re: MOS 8565 VIC-II

From: Marko Mäkelä (
Date: 2003-04-30 08:21:23

On Tue, Apr 29, 2003 at 10:13:46PM +0200, Laze Ristoski wrote:
> That's not the way it seems to me. Let's say that you write 0 at $D020,
> in an infinite loop. The dots (or sparkles as Marko calls them) will only
> appear at the border. If the VIC plots the paper area during the write
> access, you won't see any dots.

Now suppose you write 0 to $d021 in an infinite loop.  The sparkles should
appear in the text area.  I call them sparkles, because on my C128, their
width varies from about half a pixel to a full pixel.

> Aren't there any sparkle-free VICs for C128?

I'm not aware of any.

> Strange thing is that they occasionally disappear. And the lines are
> (as I already mentioned) sometimes more, sometimes less visible.

Do the sparkles disappear completely on your machine?  Try producing vertical
sparkle bars by writing a 63- or 65-cycle loop of sta $d020 on a blank screen.

> I have just tried to put an old 6569 VIC on a new board. The result
> was no picture at all. I don't dare to do the other way (new VIC on
> old board). You think I can fry it?

The analog parts of the new VIC run off 9 volts while the old VIC needs 12
volts.  If I remember correctly, Andreas Boose told me that the new VIC
overheats but works in the old C64.  Do it on your own risk. :-)


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